Preheat oven to 350˚F. Coat a 2-quart casserole dish with cooking spray. For the macaroni, place a large pot of water over high heat.  When it comes to a boil, add the macaroni and cook according to package directions. Rinse with cold water. Cover and reserve. 

Place cottage cheese and milk in a food processor and blend until smooth, about 30 to 45 seconds. Reserve. Add margarine to a medium skillet and heat over medium heat. Add onions and sauté until tender, about 5 minutes. In a large mixing bowl, combine macaroni, cottage cheese mixture, onions, cheddar cheese, parsley and pepper. Mix thoroughly. Transfer macaroni mixture to the casserole dish. Top with bread crumbs and grated cheese. Bake for about 30 minutes, or until hot and slightly bubbly. Serve warm.